Refactor `run` method in ObservableSequenceSink
Refactor `run` method in ObservableSequenceSink

It's enough to use the iterator, the second parameter `self._parent._elements` is no need.
kzaher/RxSwift,ReactiveX/RxSwift,kzaher/RxSwift,kzaher/RxSwift,ReactiveX/RxSwift,ReactiveX/RxSwift,kzaher/RxSwift